A circuit that pulls 19 amps,what size breaker would I need

Generally most circuits need to be sized 125% of the load, would need a 30 amp breaker with #10 wire.

What is the type of load on this circuit?

I'd have to disagree with the "most" part.
Some circuits do, but in a residence very few are, or must be, considered a continuous load and need the 125% multiplier.

Before giving a firm answer I'd have to ask the same question as TK. It all depends on what the circuit is being used for.
If it is for an appliance with a standard 20A plug attached it cannot be on a 30A circuit.